Hydraulic elevator

Abstract

The velocity of a cage during a time interval from the start of deceleration to the stoppage of the cage is controlled by utilizing a velocity characteristic which changes depending upon the load condition or oil temperature of a hydraulic elevator, that is, a magnitude by which the velocity characteristic during the acceleration of the cage differs from a reference running characteristic. Thus, even when the load state or the oil temperature has changed, the operating period of time of the hydraulic elevator is shortened, so that a comfortable ride, energy saving, cost reduction etc. are attained.

What is claimed is: 
     
       1. In a hydraulic elevator of the type which has a cage, a hydraulic jack, a hydraulic pressure source, a flow control valve and a control device, and in which a flow of a pressure fluid to be supplied to or discharged from the hydraulic jack is controlled thereby to raise or lower the cage directly or indirectly, the hydraulic elevator comprising:   detection means for obtaining an actual running velocity of the cage during acceleration,   memory means for storing a predetermined reference running velocity,   arithmetic means for calculating a command velocity during deceleration from said reference running velocity and the difference between said actual running velocity and a running velocity under a reference operating condition, and   drive means driven in response to said command velocity so as to cause the cage to have a floor arrival running time close to a predetermined value.   
     
     
       2. A hydraulic elevator as defined in claim 1, wherein said detection means comprises pulleys which are disposed on upper and lower sides within a hoistway in a running direction of the cage, a rope which is extended across said pulleys and a part of which is fixed to the case, and a detector which detects a movement value of said rope. 
     
     
       3. A hydraulic elevator as defined in claim 1, wherein said detection means comprises pulleys which are disposed on upper and lower sides within a hoistway in a running direction of the cage, a perforated tape which is extended across said pulleys and a part of which is fixed to the cage, and a light source and a photosensor which are disposed with said perforated tape held therebetween. 
     
     
       4. A hydraulic elevator as defined in claim 1 wherein said detection means comprises a roller which is mounted on the cage, a spring which urges said roller against a guide rail of the cage, and a detector which detects rotation of said roller. 
     
     
       5. In a hydraulic elevator of the type which has a cage, a hydraulic jack, a hydraulic pressure source, a flow control valve and a control device, and in which a flow of a pressure fluid to be supplied to or discharged from the hydraulic jack is controlled thereby to raise or lower the cage directly or indirectly; a hydraulic elevator characterized by comprising detection means to detect at least either of a velocity and a position of the cage, means to obtain an actual running velocity of the cage during acceleration thereof from a detected value of said detection means to calculate a deviation between the actual running velocity and a predetermined reference running velocity and means to determine a command velocity of the cage during deceleration thereof on the basis of the calcuIated result so as to bring a floor arrival running time close to a predetermined value, wherein the reference running velocity V s  is stored beforehand, a running velocity V 1  under a reference operating condition and the actual running velocity V 1  ' during the acceleration in the running of the cage are detected, and the command velocity V s  ' during the deceleration is calculated according to an equation of V s  '=V s  +(V 1  -V 1  ').